Metallocenyl phthalocyanines as optical recording media

ABSTRACT

Mixtures of metallocenyl phthalocyanines obtainable by reacting a mixture A comprising two phthalocyanines (I) and (II) with a metallocene derivative in the presence of a catalyst, and also oligomeric metallocenyl phthalocyanines, processes for preparing them, their use for, inter alia, optical recording and optical recording media.

[0001] The present invention relates to metallocenyl phthalocyanines,their mixtures, processes for preparing them and their use for opticalrecording.

[0002] The invention is in the field of optical data storage, preferablyfor write-once storage media. In these, the information is stored bymeans of different optical properties of a dye at written and unwrittenpoints. Such storage media are known, for example, under the name “WORM”systems (write once read many), and are further subdivided into, forexample, “CD-R” or “DVD-R”.

[0003] The use of dyes which absorb radiation in the near infraredregion (NIR region) for recording information in WORM systems isdescribed, for example, by M. Emmelius in Angewandte Chemie, number 11,pages 1475-1502 (1989). Laser irradiation can produce the changes inabsorption necessary for recording information in digital form in suchrecording materials by means of physical (for example by sublimation ordiffusion) or chemical changes (for example photochromy, isomerizationor thermal decomposition of the dye).

[0004] Substituted phthalocyanines represent an important class of dyesfor use in such WORM systems, since they have strong NIR absorptions inthe range from 700 nm to 900 nm when appropriately substituted,regardless of the central metal atom which is customarily present.

[0005] The recording layer to be used has to meet very demandingrequirements such as high index of refraction and low absorption at thelaser wavelength, high contrast of the written pits, uniformity of thepit with different pit lengths, high light stability in daylight andunder weak laser radiation (reading) while at the same time having ahigh sensitivity under intense laser radiation (writing), high long-termstability, low noise, high resolution and, as a particularly importantaspect, a very small systematic and random deviation (“jitter”) of thepit lengths from a prescribed value at optimum writing power.

[0006] Since the recording layer is generally applied from a solution,for example by spin coating, the dyes should be readily soluble incustomary solvents, for example as described in EP-A 511 598(independently of the distinction between polar and nonpolar solventsmade there).

[0007] Polymeric or oligomeric phthalocyanines, i.e. compoundscomprising at least two phthalocyanine units which are generallyconnected to one another via a single bond or an atom or moleculeserving as a bridge, for optical recording are known per se. Forexample, JP-A 59073994 describes polymeric recording materials whichhave macrocycles made up of phthalocyanines in the main chain.

[0008] JP-A 59229396 describes recording materials comprising dyeoligomers in which at least two molecules, for example phthalocyaninescontaining vanadium or vanadium oxide, VO, as central atom, areconnected to one another by a —COO group or a unit containing at leasttwo —COO groups.

[0009] JP-A 62059285 describes phthalocyanine compounds of the formulaPc-(CONH-L-OH)_(n), where Pc is a phthalocyanine radical containing acentral atom, e.g. Co(II), L is C₁-C₅alkylene and n is a number greaterthan or equal to one, which can be polymerized by polyaddition orpolycondensation.

[0010] GB-A 2259517 describes polymeric phthalocyanines of the formula(Q-X—)_(q)Pc(-X-Q-Y)_(p), where X is O, S, Se, Te, NH, N-alkyl orN-aryl, Q is a carbon atom or an aromatic or heterocyclic radical, Y isa reactive group capable of forming a bridge and p≧2 , q≧0, 16≧(p+q).

[0011] Phthalocyanine compounds containing at least one ferrocene unitas substituent are likewise known. Thus, for example, J. Organomet.Chem. 468(1-2) (1994) 205-212 describes 1, 1,″,1″″,1″″″-(29H,31H-phthalocyanine-2,9,16,23-tetrayl)tetrakisferrocene, Chin. Chem.Lett. 4(4) (1993) 339-342 describes [1-(11-ferrocenylundecyl)-1′-[4-[4-[[9,16,23-tris(2,2-dimethylpropoxy)-29H,31H-phthalocyanin-2-yl]oxy]phenoxy]butyl]-4,4′-bipyridiniumato(2-)-N²⁹,N³⁰, N³¹, N³²]zinc dibromide, New J. Chem. 21(2) (1997) 267-271describes 1,1″-[[9,23-bis(dodecylthio)-29H,31H-phthalocyanine-2,16-diyl]bis(nitrilomethylidine)]bisferrocene and J.Organomet. Chem. 541(1-2) (1997) 441-443 describes the synthesis of[Cp(dppe)Fe—CN—MnPc]₂O (where dppe=1,2-ethanediylbis(diphenylphosphine);Cp=cyclopentadienyl; Pc=phthalocyanine).

[0012] J. Chem. Soc., Chem. Commun. 1995, 1715-1716, describes thepreparation of liquid-crystalline ferrocenyl phthalocyanines by reactingferrocene carbonyl chloride with a metal-free phthalocyanine bearing ahydroxy group as substituent to form the corresponding ester compound.

[0013] Inorg. Chem. 37 (1998) 411-417 describes the synthesis ofbis(ferrocenecarboxylato)(phthalocyaninato)silicon, with the ferroceneunit being bound to the central atom.

[0014] WO-A 9723354 describes optical recording materials based onphthalocyanines having ferrocene units bound as substituents to, interalia, the central atom.

[0015] WO-A 0009522 describes a metallocenyl phthalocyanine or a complexof this with a divalent metal, oxo-metal, halo-metal or hydroxy-metal inwhich at least one of the four phenyl rings of the phthalocyanine bearsat least one metallocene radical as substituent bound via a bridgingunit E, where E is composed of a chain of at least two atoms or atomgroups selected from the group consisting of —CH₂—, —C(═O)—,—CH(C₁-C₄alkyl)-, —C(C₁-C₄alkyl)₂-, —NH—, —S—, —O— and —CH═CH—.

[0016] The use of CD-R as archiving and backup medium for computer datais increasingly requiring faster writing speeds. On the other hand, whenit is to be used as an audiomedium, slow (1×) speeds are desired. Thisleads to the recording layers continually having to be reoptimized forsuch broad-band behaviour (until recently 1×-8×, at present 1×-16×, infuture 24× and above), which places extraordinarily high demands on therecording layers to be used. It is known that recording layerscomprising phthalocyanines display good measured values for intermediatespeeds (2×-8×), but less favourable 1× values for the contrast and thelength deviation of the pits and lands from the prescribed values andalso for their random fluctuations (“jitter”).

[0017] The term contrast refers to the reflection difference between pitand land or the corresponding modulation amplitude of the high frequencysignal. The term jitter refers specifically to a time defect in thechange in signal which is attributable to a pit being too short or toolong. For example, in a CD-R, the length of the pits or the lands canvary in the range from 3T to 11T, where 1T=231.4 ns at a speed of 1.2m/s (1×). When, for example, the length of a 3T pit is only slightly tooshort or too long, this can lead to an increased number of BLERs (=blockerror rate, which refers to the number of physical errors present on theCD) and thus to lower quality. The BLER should, in accordance with theapplicable standard, be less than 220 per second, and in accordance withpresent market requirements, even below 10-20 per second. Therequirements which the recording medium has to meet and the applicablestandards (at present laid down in the “orange book”) are known to thoseskilled in the art, so that further explanations on this subject aresuperfluous.

[0018] Various proposals for solving the abovementioned difficultiesassociated with phthalocyanines have been made; in particular, attemptshave been made to reduce the relatively high decomposition temperaturecompared with other classes of dyes, in particular cyanines.

[0019] Thus, the DE-A 4 112 402 proposes a mixture of a phthalocyanineand a cyanine (as light-absorbent element) which absorbs in theabovementioned wavelength range as recording film. However, here too,repeated reading leads to destruction of the light absorber, so that thedesired properties are not achieved. In addition, it is known thatcyanine dyes are not lightfast and it is therefore usually necessary toadd a stabilizer.

[0020] EP-A 600 427 describes an optical recording medium whoserecording layer comprises a phthalocyanine and an additive, e.g. aferrocene derivative, a metal acetylacetonate or an antiknock agent.According to that application, the addition of the stated additivesimproves the recording quality. However, disadvantages are the use of anadditional substance in the form of an additive and difficulties in therecovery of the dye left during production of the recording layer, sinceit is necessary either to remove the active or to readjust itsconcentration to allow reuse.

[0021] JP-A 8-118800 describes optical recording media whose recordinglayers comprise an azo compound substituted by a ferrocene unit.Mixtures of these azo compounds with, inter alia, phthalocyanines andpentamethinecyanines are also described. A disadvantage here is that asatisfactory recording layer cannot be obtainedlusing either the azocompound or the phthalocyanines alone.

[0022] WO-0009522, which has already been discussed above, describesmetallocenyl phthalocyanines which can be used as recording materials inoptical information storage media and, without further additives,preferably when used in CD-Rs, have significantly improved broad-bandbehaviour (1×-8×) compared to the previous state of the art and displayexcellent recording and reproduction characteristics at the wavelengthof a semiconductor laser (770-790 nm). Furthermore, these compounds makepossible an improved process for recovering the dye used in productionof the recording layer. However, the recording materials known hithertoare not able to fully meet the increased requirements at very highwriting speeds. In particular, it is found that the optimum thickness ofthe recording layer is different for different writing speed ranges.While at low writing speeds (1×-2×), an unsatisfactorily low contrast(I11) is generally the critical parameter which can be improved by arelatively thick layer, while at higher writing speeds (≧4×), thecritical parameter is generally excessive jitter at short pits or lands(in particular L3T), which can be reduced by a relatively thin recordinglayer. On the other hand, a thin layer requires, undesirably, anincreased writing power at a given writing speed, which once againlimits the maximum achievable writing speed at a given laser power.

[0023] There is therefore a need for improved recording materials whichcan meet all required specifications over a broadband, i.e. both at low(1×-2×) and very high (≧12×) writing speeds, at one and the same layerthickness and can also be written on at a comparatively low laser power,i.e. has a high sensitivity. Furthermore, it is desirable for productionreasons for the broad-band quality to be obtained not only at aparticular layer thickness but within the widest possible thicknessrange, viz. the “processing window”. An adequate measure of the scalingof the processing window is the optical density of the recording layer.Accordingly, it is desirable to have recording materials which have avery large positive numerical value of the width of the processingwindow, while a negative numerical value means that there is no layerthickness at which all specifications can be met over a broadband.

[0024] It is therefore an object of the present invention to provide newbroad-band recording materials having a large processing window, i.e. animproved positive processing window, and a high sensitivity. Inparticular, optical recording media having a low layer thickness,improved recycling and writing speeds from above 32× to at least 40× areto be made available.

[0025] Accordingly, the claimed mixtures, metallocenyl phthalocyaninecompounds, processes for preparing them, their use, optical recordingmedia comprising these mixtures or compounds and values have been found.

[0026] In particular, the present invention provides mixtures ofmetallocenyl phthalocyanines obtainable by reacting a mixture Acomprising

[0027] (a) from 1 to 99% by weight, preferably from 50 to 95% by weight,of a phthalocyanine of the formula I

[0028] where M₁ is a divalent metal, an oxo-metal group, a halo-metalgroup or a hydroxy-metal group or two hydrogen atoms, where one or twoligands may be bound to the divalent metal atom, the oxo-metal group,the halo-metal group or the hydroxy-metal group,

[0029] X is halogen such as chlorine, bromine or iodine, preferablychlorine or bromine,

[0030] Y₁ is —OR₁, —OOC—R₂, —NHR₁, —N(R₁)R₂, —SR₁, preferably —OR₁,

[0031] Y₂ is —CHO, —CH(OR₃)OR₄, —CH═N—OH, —CH═N—OR₃, —CH═N—NHR₅,—CH═N—N(R₃)R₅, —CH₂OH, —(CH₂)₂₋₂₀OH, —CH₂OR₃, —CH₂OOC—R₃, —CO—R₃, —COOHor —COOR₃,

[0032] R₁ to R₅ can each be, independently of one another, unsubstitutedor halogen-, hydroxy-, C₁-C₂₀alkoxy-, C₁-C₂₀alkylamino- orC₂-C₂₀dialkylamino-substituted C₁-C₂₀alkyl, which may be interrupted by—O—, —S— or

[0033] —NR₁₁—, where R₁₁ can be C₁-C₆alkyl,

[0034] and R₁ and R₂ may also be

[0035] C₅-C₂₀cycloalkyl, C₂-C₂₀alkenyl, C₅-C₁₂cycloalkenyl,C₂-C₂₀alkynyl, C₆-C₁₈aryl or C₇-C₁₈aralkyl,

[0036] x is a rational number from 0 to 8, preferably from 0 to 5,particularly preferably from 0 to 3,

[0037] y₁ is a rational number from 0 to 6, preferably an integer from 1to 6, particularly preferably from 3 to 5, very particularly 4,

[0038] y₂ is a rational number from 0 to 4, preferably from 0 to 2,particularly preferably from 0 to 1,

where (x+y ₁ +y ₂)≦16, and

[0039] R₁₅ can be a hydroxyl-containing radical, a carboxyl-containingradical or a radical containing an acid chloride group, preferably—CH₂OH, —CH(Me)OH, —COOH, —COCl, and

[0040] (b) from 99 to 1% by weight, preferably from 50 to 5% by weight,of a phthalocyanine of the formula II

[0041] with a metallocene derivative in the presence of a catalyst.

[0042] As divalent metal, it is possible to use divalent transitionmetal cations, in particular those of copper, zinc, nickel, palladium,platinum, manganese or cobalt, preferably palladium or copper.

[0043] As oxo-metal group, it is possible to use VO, MnO or TiO.

[0044] As halo-metal group, it is possible to use Al—Cl, Al—Br, Al—F,Al—I, Ga—Cl, Ga—F, Ga—I, Ga—Br, In—Cl, In—F, In—I, In—Br, Tl—Cl, Tl—F,Tl—I, Tl—Br, FeCl or RuCl, or CrCl₂, SiCl₂, SiBr₂, SiF₂, Sil₂, ZrCl₂,GeCl₂, GeBr₂, Gel₂, GeF₂, SnCl₂, SnBr₂, Snl₂, SnF₂, TiCl₂, TiF₂, TiBr₂.

[0045] As hydroxy-metal group, it is possible to use MnOH, Si(OH)₂,Ge(OH)₂, Zr(OH)₂, Mn(OH)₂, AlOH or Sn(OH)₂.

[0046] C₁-C₂₀ Alkyl is, for example, methyl, ethyl, n-, i-propyl, n-,sec-, i-, tert-butyl, n-, neo-pentyl, hexyl, heptyl, octyl, nonyl,decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,heptadecyl, octadecyl, nonadecyl, eicosyl, preferably C₁-C₁₂alkyl suchas methyl, ethyl, n-, i-propyl, n-, sec-, i-, tert-butyl, n-,neo-pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl or, inparticular, branched C₃-C₁₂alkyl such as i-propyl, sec-, i-, tert-butyl,neo-pentyl, 1,2-dimethylpropyl, 1,3-dimethylbutyl, 1-isopropylpropyl,1,2-dimethylbutyl, 1,4-dimethylpentyl, 2-methyl-1-isopropylpropyl,1-ethyl-3-methylbutyl, 3-methyl-1-isopropylbutyl,2-methyl-1-isopropylbutyl or 1-tert-butyl-2-methylpropyl and C₁-C₆alkylsuch as methyl, ethyl, n-, i-propyl, n-, sec-, i-, tert-butyl, n-,neo-pentyl, n-hexyl, 2,2-dimethylhexyl, particularly preferablyC₁-C₄alkyl such as methyl, ethyl, n-, i-propyl, n-, sec-, i-, tert-butylor 2,4-dimethyl-3-pentyl.

[0047] C₅-C₂₀Cycloalkyl is, for example, cyclopentyl, cyclohexyl,cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl,cyclododecyl, cyclotridecyl, cyclotetradecyl, cyclopentadecyl,cyclohexadecyl, cycloheptadecyl, cyclooctadecyl, cyclononadecyl,cycloeicosyl, preferably C₅-C₈cycloalkyl such as cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, or bicycloalkyl such as

[0048] where Xp, Yp and Zp can each be, independently of one another,hydrogen, halogen, methyl or ethyl, and Rp₁ to Rp₆ can each be,independently of one another, C₁-C₄alkyl which may be unsubstituted orhalogen-substituted. Preferred bicycloalkyl radicals are, for example,derivatives such as

[0049] The preparation of phthalocyanines bearing such bicycloalkylligands is described in detail in U.S. Pat. No. 6,348,250, so thatfurther details on this subject are superfluous here.

[0050] C₁-C₂₀Alkenyl is, for example, ethenyl, n-, i-propenyl, n-, sec-,i-, tert-butenyl, n-, neo-pentenyl, hexenyl, heptenyl, octenyl, nonenyl,decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl,hexadecenyl, heptadecenyl, octadecenyl, nonadecenyl, eicosenyl,preferably C₂-C₆alkenyl such as ethenyl, n-, i-propenyl, n-, sec-, i-,tert-butenyl, n-, neo-pentenyl, n-hexenyl, particularly preferablyC₂-C₄alkenyl such as ethenyl, n-, i-propenyl, n-, sec-, i-,tert-butenyl.

[0051] C₅-C₁₂Cycloalkenyl is, for example, cyclopentenyl, cyclohexenyl,cycloheptenyl, cyclooctenyl, cyclononenyl, cyclodecenyl, cycloundecenyl,cyclododecenyl, preferably C₅-C₈cycloalkenyl such as cyclopentenyl,cyclohexenyl, cycloheptenyl, cyclooctenyl.

[0052] C₂-C₂₀Alkynyl is, for example, ethynyl, n-, i-propynyl, n-, sec-,i-, tert-butynyl, n-, neo-pentynyl, hexynyl, heptynyl, octynyl, nonynyl,decynyl, undecynyl, dodecynyl, tridecynyl, tetradecynyl, pentadecynyl,hexadecynyl, heptadecynyl, octadecynyl, nonadecynyl, eicosynyl,preferably C₂-C₆alkynyl such as ethynyl, n-, i-propynyl, n-, sec-, i-,tert-butynyl, n-, neo-pentynyl, n-hexynyl, particularly preferablyC₂-C₄alkynyl such as ethynyl, n-, i-propynyl, n-, sec-, i-,tert-butynyl.

[0053] C₆-C₁₈Aryl is, for example, phenyl, 1-, 2-naphthyl, indenyl,azulenyl, acenaphthylenyl, fluorenyl, phenanthrenyl, anthracenyl,triphenylene, preferably phenyl.

[0054] C₇-C₁₈Aralkyl is, for example, benzyl, phenethyl,phenyl-(CH₂)₃₋₁₂—, preferably benzyl.

[0055] C₁-C₂₀Alkoxy is, for example, methoxy, ethoxy, n-, i-propoxy, n-,sec-, i-, tert-butoxy, n-, neo-pentoxy, hexoxy, heptoxy, octoxy, nonoxy,decoxy, undecoxy, dodecoxy, tridecoxy, tetradecoxy, pentadecoxy,hexadecoxy, heptadecoxy, octadecoxy, nonadecoxy, eicosoxy, preferablyC₁-C₆alkoxy such as methoxy, ethoxy, n-, i-propoxy, n-, sec-, i-,tert-butoxy, n-, neo-pentoxy, n-hexoxy, 2,2-dimethylhexoxy, particularlypreferably C₁-C₄alkoxy such as methoxy, ethoxy, n-, i-propoxy, n-, sec-,i-, tert-butoxy.

[0056] C₁-C₂₀Alkylamino is, for example, methylamino, ethylamino, n-,i-propylamino, n-, sec-, i-, tert-butylamino, n-, neo-pentylamino,hexylamino, heptylamino, octylamino, nonylamino, decylamino,undecylamino, dodecylamino, tridecylamino, tetradecylamino,pentadecylamino, hexadecylamino, heptadecylamino, octadecylamino,nonadecylamino, eicosylamino, preferably C₁-C₆alkylamino such asmethylamino, ethylamino, n-, i-propylamino, n-, sec-, i-,tert-butylamino, n-, neo-pentylamino, n-hexylamino, particularlypreferably C₁-C₄alkylamino such as methylamino, ethylamino, n-,i-propylamino, n-, sec-, i-, tert-butylamino.

[0057] C₂-C₂₀Dialkylamino is, for example, dimethylamino, diethylamino,n-, i-dipropylamino, n-, sec-, i-, tert-dibutylamino, n-,neo-dipentylamino, dihexylamino, diheptylamino, dioctylamino,dinonylamino, didecylamino, diundecylamino, didodecylamino,ditridecylamino, ditetradecylamino, dipentadecylamino, dihexadecylamino,diheptadecylamino, dioctadecylamino, dinonadecylamino, dieicosylamino,preferably C₁-C₆alkylamino such as dimethylamino, diethylamino, n-,i-dipropylamino, n-, sec-, i-, tert-dibutylamino, n-, neo-dipentylamino,n-dihexylamino, particularly preferably C₁-C₄alkylamino such asdimethylamino, diethylamino, n-, i-dipropylamino, n-, sec-, i-,tert-dibutylamino.

[0058] As phosphorus-containing C₁-C₄alkyl, preference is given to usingmethylene, ethylene, propylene or butylene substituted bydiphenylphosphine radicals, e.g. —CH₂—PAr₂ or —CH(Me)-PAr₂, where Ar isunsubstituted or substituted phenyl.

[0059] As diarylphosphines, it is possible to use, for example,diphenylphosphine and substituted diphenylphosphines.

[0060] The reaction according to the invention is generally carried outby esterification of the mixture A by means of a metallocene derivativein the presence of a catalyst, by reacting the mixture A with ametallocene derivative, preferably one selected from the groupconsisting of hydroxyl-containing metallocenes, carboxyl-containingmetallocenes and metallocenes containing an acid chloride group,preferably from the group consisting of metallocene carbonyl chloridesCpM₂Cp′-COCl, metallocenecarboxylic acids CpM₂Cp′-COOH, where Cp is

[0061] and metallocene alcohols, generally in a manner known per se.

[0062] Particular preference is given to using a mixture A in which R₁₅is a hydroxyl-containing radical and the metallocene bears acarboxyl-containing radical or a radical containing an acid chloridegroup. Equal preference is given to the variant in which R₁₅ is acarboxyl-containing radical or a radical containing an acid chloridegroup and the metallocene is a hydroxyl-containing radical.

[0063] The reaction can likewise be carried out in a manner known per seby condensation of two hydroxyl-containing radicals to form an ether orby fusion of one hydroxyl-containing radical with an amine-containingradical to form a urethane.

[0064] The other above-described possible radicals for R₁₅ arepreferably obtainable by analogous methods.

[0065] The starting compounds I and II can, if they have anOH-containing substituent, generally be obtained by reduction ofcorresponding formyl compounds, preferably the corresponding aldehyde,for example by the process described in WO 98/14520. The reduction of analdehyde is preferably carried out using a complex metal hydride such assodium borohydride. The reduction is particularly preferably carried outusing a complex metal hydride on an inert support material such as azeolite, a filter aid, a silicate, an aluminium oxide (“Alox”), veryparticularly preferably using sodium borohydride on Alox. The carboxylgroup can be obtained in a manner known per se by oxidation of thecorresponding formyl compound, and can, if desired, be converted intothe corresponding acid chloride.

[0066] The formyl compounds are themselves obtained, for example, by amethod also described in WO 98/14520 by reacting the phthalocyanines III

[0067] known from, for example, EP-B 373 643 in a Vilsmeler reactionwith, preferably, phosphorus oxychloride/dimethylformamide or phosphorusoxychloride/N-methylformanilide.

[0068] The corresponding halogenated compounds I to III (for x≠0) areobtained, for example, by halogenation of the corresponding formylcompounds before then being reduced to give the corresponding alcoholcompounds V.

[0069] The halogenation can be carried out by customary methods asdescribed in EP-A 513,370 or EP-A 519,419, for example by admixing thedesired phthalocyanines with bromine in an organic solvent such as asaturated hydrocarbon, ether or halogenated hydrocarbon or, as in themethod described in EP-A 703,281, in a two-phase system comprising waterand a halogenated aromatic solvent which is essentially immiscible withwater, if desired with heating. The halogenation can equally well becarried out only after reaction of the mixture A with the metallocenederivatives.

[0070] As metallocene carbonyl compounds, preference is given to usingferrocenecarboxylic acid and derivatives such as esters and halides,preferably ferrocenecarboxylic acid,

[0071] Metallocene carbonyl compounds are generally commerciallyavailable or are obtainable by known methods as described in Org.Synthesis 56 (1977) 28-31. Ferrocene derivatives are also obtainable bythe methods described in “The Synthesis of Substituted Ferrocenes andOther π-Cyclopentadienyl-Transition Metal Compounds, Org. Reactions 17,1969, 1/154, 21/3, 99/100”. Specifically, the abovementionedferrocenylacetic acid is obtainable by the following synthetic route:

[0072] Org. Syn. 40, 1960, 31/3, 45/6, 52; J. Chem. Soc.,1958, 656-660

[0073] Org. Syn. 40, 1960, 31/3,4516, 52; J. Org. Chem. 23, 1958,653-655

[0074] Further ferrocene derivatives such as ferrocenylbutyric acid orferrocenoylpropionic acid are described, for example, in J. Am. Chem.Soc. 79, 3420-3424 (1957); Docd. Acad. Nauk SSSR 118, 1958, 512/4; Proc.Acad. Sci. USSR Chem. Sect. 118, 1958, 81/3; U.S. Pat. No. 3,222,373.Bifunctional ferrocene derivatives such as ferrocenedicarboxylic acid or1,1′-bishydroxymethylferrocene can also be incorporated as a bridgebetween two phthalocyanine units. The preparation of, for example,ferrocenedicarboxylic acid is carried out by a method similar to that ofJ. Polymer Sci., 54, 651 (1961); 1,1′-bishydroxymethylferrocene iscommercially available (e.g. ALDRICH, No. 37,262-5, RegistryNo.1291-48-1 CHEMCATS).

[0075] The molar ratio of metallocene carbonyl compound to the mixture Ausually depends on the desired degree of esterification and the molarratio of the phthalocyanines I and II. Preference is given to a rangefrom 5:1 to 0.5:1, particularly preferably from 2:1 to 1:1.

[0076] The reaction is usually carried out in a solvent. Solvents usedare, for example, aprotic organic solvents such as pyridine,chlorobenzene, toluene, xylene, tetrahydrofuran, chloroform, methylenechloride or ethyl acetate, or mixtures thereof.

[0077] Preference is given to using solvent mixtures comprising arelatively low-boiling polar solvent and a relatively high-boilingnonpolar solvent, in particular when an acid-catalyzed esterificationusing a carboxylic acid or a carboxylic ester (transesterification) iscarried out. Depending on the solubility of the ferrocene derivativeused, the addition of a polar solvent may also be dispensed with.

[0078] The relatively low-boiling polar solvent is then preferablydistilled off together with the resulting water (or alcohol) of reactionfrom the reaction mixture during the course of the reaction.

[0079] The weight ratio of polar to nonpolar solvent is usually in therange from 10:1 to 1:10, preferably from 4:1 to 1:1.

[0080] The weight ratio of solvent mixture to mixture A is generally inthe range from 2:1 to 50:1, preferably from 5:1 to 20:1.

[0081] As catalysts for the reaction, preference is given to using acidsas are customary in the esterification of alcohols with carboxylic acidsor in the esterification of two alcohol components:

[0082] These are, for example:

[0083] Mineral acids such as H₂SO₄, HCl, HBr, HClO₄, H₃PO₄,

[0084] Aromatic sulphonic acids of the formula Ar—SO₃H, e.g.p-toluenesulphonic acid

[0085] Lewis acids such as FeCl₃, AlCl₃, ZnCl₂, TiOR₄ (whereR═C₁-C₆alkyl), dibutyltin oxide, dioctyltin oxide.

[0086] The amount of catalyst is generally, depending on the catalyst,in the range from 0.01% by weight to 20% by weight, based on the mixtureA used. In the case of the strong mineral acids and Lewis acids, amountsof from 0.1 to 1% by weight are usually sufficient.

[0087] The reaction temperature is usually in the range from 0° C. tothe reflux temperature of the reaction mixture under ambient pressure,preferably from room temperature (20° C.) to 130° C. The reactiontemperature usually depends on the solvent used or the chosencomposition of the solvent mixture.

[0088] On the basis of observations to the present time, the reactionpressure is not critical to the success of the invention. It isadvantageously chosen in the range from 70 kPa to 5 MPa, preferably from90 to 120 kPa.

[0089] The reaction is preferably carried out in an inert gas atmospheresuch as nitrogen or a noble gas such as neon or argon.

[0090] The mixtures of the invention can also be obtained by reducingthe formyl compounds obtainable from the phthalocyanines III by themethod described in WO 98/14520, for example by means of sodiumborohydride, to form the corresponding alcohol compounds subsequentlyesterifying the latter with a metallocenyl radical and then, if desired,halogenating the products.

[0091] A further embodiment of the present invention provides mixturesaccording to the invention which comprise the following main components:

[0092] (a) from 1 to 99% by weight, preferably from 20 to 95% by weight,particularly preferably from 40 to 90% by weight, very particularlypreferably from 50 to 80% by weight, of a metallocenyl phthalocyanine IVor its metal complex with a divalent metal, oxo-metal, halo-metal orhydroxy-metal, in which at least one of the four phenyl rings of thephthalocyanine bears at least one metallocene radical as substituentbound via a bridging unit E, where E comprises a chain of at least twoatoms or atom groups selected from the group consisting of —CH₂—,—C(═O)—, —CH(C₁-C₄alkyl)-, —C(C₁-C₄alkyl)₂-, —NH—, —S— and —O—, or amixture of different metallocenyl phthalocyanines IV,

[0093] and

[0094] (b) from 99 to 1% by weight, preferably from 80 to 5% by weight,particularly preferably from 60 to 10% by weight, very particularlypreferably from 50 to 20% by weight, of a metallocenyl phthalocyaninecompound selected from the group consisting of phthalocyanine compoundsV comprising two phthalocyanine units linked via a single bond or abridging atom or molecule, phthalocyanine compounds VI comprising threephthalocyanine units linked in each case via a single bond and/or abridging atom or molecule and phthalocyanine compounds VII comprisingfour phthalocyanine units linked in each case via a single bond and/or abridging atom or molecule.

[0095] Preferred metallocenyl phthalocyanines IV or their metalcomplexes are ones having the formula IVa:

[0096] where

[0097] R₃ is

[0098] preferably

[0099] where R₄ and R₅ can each be, independently of one another,hydrogen or C₁-C₄alkyl,

[0100] n is from 1 to 4,

[0101] R₆ and R₇ are each, independently of one another, hydrogen,halogen such as fluorine, chlorine, bromine or iodine, C₁-C₄alkyl,C₁-C₄alkoxy, amino-C₁-C₄alkyl, diarylphosphine or phosphorus-containingC₁-C₄alkyl such as —CH₂—PAr₂ or —CH(Me)-PAr₂, where Ar is unsubstitutedor substituted phenyl, R₈ can be —O—R₉—, —C(═O)—O—R₉ or —O—C(═O)—R₉—,where R₉ can be a single bond, C₁-C₄alkylene or C₂-C₄alkenylene, and M₂is a divalent transition metal, and R₁₂ is hydrogen or methyl and R₁₃ isa single bond, —CH₂—, —CH₂CH₂—, —CH═CH—, —CH₂—C(═O)— or —CH₂CH₂—C(═O)—,

[0102] z is from 1 to 4, preferably from 1 to 3, particularly preferablyfrom 1 to 2,

where (x+y ₁ +y ₂ +z)≦16,

[0103] and one or two ligands may be bound to the divalent metal atom,the oxo-metal group, the halo-metal group or the hydroxy-metal group,and E is, as indicated further above, a molecular chain selected fromthe group of consisting of —CH₂—, —C(═O)—, —CH(C₁-C₄alkyl)-,—C(C₁-C₄alkyl)₂-, —NH—, —S— and —O—.

[0104] Rational or nonintegral values of z, x, y₁ and y₂ (and also a2 toa8 below) indicate that a mixture of at least two different compounds IVis present, with the molar ratio of the two compounds leading to thecorresponding rational number. Thus, for example, z=1.5 would mean thata compound of the formula IV in which z=1 and another compound IV inwhich z=2 are present in a molar ratio of 1:1.

[0105] It may also be pointed out that corresponding structural isomershaving different substitution positions on the phenyl rings are includedunder the general formula, but are not shown in the interest of clarity.

[0106] These two remarks apply to all formulae depicted in the presentpatent application.

[0107] Particularly preferred metallocenyl phthalocyanines have theformula IVb

[0108] where x=2.6 to 3.0, preferably from 2.7 to 2.9, in particular2.8, or the formula IVc

[0109] where=0 to 0.5, preferably 0.

[0110] Preference is also given to mixtures of different metallocenylphthalocyanines IV comprising

[0111] (a) from 60 to 95 mol %, preferably from 80 to 95 mol %, of acompound IVd

[0112] having one radical R₃(z=1),

[0113] (b) from 5 to 20 mol %, preferably from 5 to 10 mol %, of acompound IVd having two radicals

R₃(z=2)

[0114] and

[0115] from 0 to 25 mol %, preferably from 0 to 10 mol %, of a compoundIVe

[0116] where the radicals —OR₁₁, R₃═R₁₄, X and M₃ are each the same inthe formulae IVd and IVe and are otherwise as defined above, and the mol% figures add up to 100%.

[0117] Furthermore, particular preference is given to mixtures ofdifferent metallocenyl phthalocyanines IV comprising

[0118] (a) from 60 to 95 mol %, preferably from 80 to 95 mol %, of acompound IVd in which R₁₁ is C₁-C₁₂alkyl and M₃ is palladium or copperand z is 1,

[0119] (b) from 5 to 20 mol %, preferably from 5 to 10 mol %, of acompound IVd having two radicals R₃(z=2)

[0120] and

[0121] (c) from 0 to 25 mol %, preferably from 0 to 10 mol %, of acompound IVe in which R₁₄ is —CHO, —CH₂OH, —COOH, —CH₂OC(O)—C₁-C₄alkylor an acetal and z can be 1 or 2, where the radicals —OR₁₁, R₃═R₁₄, Xand M₃ are each the same in the formulae IVd and IVe and are otherwiseas defined above, and the mol % figures add up to 100%.

[0122] A further embodiment of the present invention providesmetallocenyl phthalocyanine compounds selected from the group consistingof phthalocyanine compounds V comprising two phthalocyanine units linkedvia a single bond or a bridging atom or molecule, phthalocyaninecompounds VI comprising three phthalocyanine units linked in each casevia a single bond and/or a bridging atom or molecule and phthalocyaninecompounds VII comprising four phthalocyanine units linked in each casevia a single bond and/or a bridging atom or molecule.

[0123] The metallocenyl phthalocyanines V, VI and VII and higheroligomers can be represented by the formula VIII

(Pc)_(a1),(Xa)_(a2)(Ya)_(a3)(Za)_(a4)(Ma)_(a5)(-L-)_(a6)   VIII

[0124] where Pc is phthalocyanine or its metal complex of a divalentmetal, oxo-metal, halo-metal, hydroxy-metal or 2 hydrogen atoms, and theterms divalent metal, oxo-metal, etc., are as defined above,

[0125] Xa, Ya, Za, Ma and -L- are substituents on the peripheral carbonskeleton, in particular Xa is halogen, Ya is substituted orunsubstituted alkoxy, alkylamino or alkylthio, Za is a formyl, carbonyl,hydroxymethyl or carboxy group, Ma is a substituent comprising at leastone metallocene radical, -L- is a single bond, —(CH₂)_(a7)—, where a7=1,2, 3 or 4, an ether group such as —O— or —(CH₂)_(a7)—O—(CH₂)_(a8)—,where a8=1, 2, 3 or 4, an ester group, an amide group or a divalentmetallocenyl group, and

[0126] a1 is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10,

[0127] a2 is a rational number from 0 to 8, preferably from 0 to 5,particularly preferably from 0 to 3,

[0128] a3 is a rational number from 0 to 6, preferably an integer from 1to 6, particularly preferably from 3 to 5, very particularly preferably4,

[0129] a4 is a rational number from 0 to 4, preferably from 0 to 2,particularly preferably from 0 to 1,

[0130] a5 is a rational number from 0 to 4, preferably from 0 to 2,

[0131] a6 is a rational number from 1 to 4, preferably from 1 to 3,

where (a2+a3+a4+a5+a6)≦16 and 1≦(a4+a5+a6)≦4.

[0132] Particularly preferred oligomeric phthalocyanines of the formulaeV to VII and further oligomers having more than four phthalocyanineunits have the formula IX

[0133] where

[0134] M₁ is as defined above,

[0135] Xa is halogen such as chlorine, bromine or iodine, preferablychlorine or bromine,

[0136] Ya is preferably —OR₁, —OOC—R₂, —NHR₁, —N(R₁)R₂, —SR₁, preferably—OR₁,

[0137] Za is preferably —CHO, —CH(OR₃)OR₄, —CH═N—OH, —CH═N—OR₃,—CH═N—NHR₅, —CH═N—N(R₃)R₅, —CH₂OH, —(CH₂)₂₋₂₀OH, —CH₂OR₃, —CH₂OOC—R₃,—CO—R₃, —COOH or —COOR₃,

[0138] Ma is preferably

[0139] L is preferably -E₂- or

[0140] where

[0141] M₂ and M₃ are each a divalent transition metal, preferably iron,

[0142] E₁, E₂, E₃ are each, independently of one another,—R₈(CH₂)₁₋₂₀R₉—, —R₈(COO)₁₋₂₀R₉—, —R₈OR₉—, —R₈(CONR₁₀)₁₋₂₀R₉—,preferably —(CH₂)₁₋₈—, —(CH₂)₁₋₈(COO)₁₋₈—, —(CH₂)₁₋₈O(CH₂)₁₋₈—,—(CH₂)₁₋₈(CONH)₁₋₈— or —CONH—,

[0143] R₁ to R₇ are as defined above,

[0144] R₈ and R₉ are each, independently of one another, a single bond,unsubstituted or halogen-, O—, C₁-C₄alkyl-, C₁-C₄alkoxy- orC₁-C₄alkylamino-substituted C₁-C₂₀alkylene or C₂-C₂₀alkenylene which maybe interrupted by —O—, —CO—, —S—, —NR₁₀—,

[0145] R₁₀ can be H or C₁-C₆alkyl,

[0146] R₁₁ is H, C₅-C₂₀cycloalkyl, C₂-C20alkenyl, C₅-C₁₂cycloalkenyl,C₂-C₂₀alkynyl, C₆-C₁₈aryl or C₇-C₁₈aralkyl.

[0147] A further particularly preferred embodiment provides oligomericmetallocenyl phthalocyanines IX, preferably dimeric (preferably forcompound V), trimeric (preferably for compound VI) and tetrameric(preferably for compound VII) phthalocyanines in which, preferably, M₁is Pd or Cu, Xa is Cl or Br, Ya is —OCH(CHMe₂)₂, Ma is —CH₂OC(═O)Fc (Fcis an unsubstituted ferrocene unit, —FeCp₂) and L is —CH₂—, —CH₂OCH₂— or—CH₂OC(═O)FcC(═O)OCH₂—,

[0148] a2 is from 0 to 4, a3 is from 2 to 6, particularly preferably 4,a4 is from 0 to 2, a5 is from 0 to 3, a6 is from 1 to 3, where a5+a6 isless than or equal to 3, and Ya, Ma and L are preferably bound topositions 1, 4, 5, 8, 9, 12, 13, 16 of the phthalocyanine skeleton ofthe formula IX.

[0149] Particularly preferred phthalocyanines of the formulae IX and Vto VII are:

[0150] In these formulae:

[0151] is copper tetra(α-2,4-dimethyl-3-pentoloxy)phthalocyanine

[0152]

[0153] is ferrocene, i.e. —FeCp₂

[0154] where the bridging units which join the individual phthalocyanineunits to one another, i.e. in particular —CH₂—O—CH₂— and —CH₂—, and alsothe bridging units L are preferably located in the para positionrelatively to the alkoxy group (Ya).

[0155] A particularly preferred embodiment of the present inventionprovides a novel compound of the formula VIII or of the more specificformula IX in which a1 is 1, a2 is zero, Ya is 2,4-dimethyl-3-pentyloxy,a3 is 4, a4 is zero, a5 is zero, a6 is 1 and L is —CH₂—O—CH₂—,and whichhas the specific formula IXa

[0156] where

[0157] is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine and Lis preferably located in the para position relative to Ya.

[0158] A particularly preferred embodiment of the present inventionprovides a novel compound of the formula VIII or of the more specificformula IX in which a1 is 2, a2 is zero, Ya is 2,4-dimethyl-3-pentyloxy,a3 is 4, a4 is zero, a5 is 1, Ma is —CH₂—OCO—FeCp₂, a6 is 1, and L is—CH₂—O—CH₂—, and which has the specific formula IXb

[0159] where

[0160] is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine, L ispreferably located in the para position relative to Ya and

[0161] is FeCp₂.

[0162] A further particularly preferred embodiment of the presentinvention provides a novel compound of the formula VIII or the morespecific formula IX in which a1 is 3, a2 is zero, Ya is2,4-dimethyl-3-pentyloxy, a3 is 4, a4 is zero, a5 is 0, a6 is 2, and Lis —CH₂—O—CH₂—, and which has the specific formula IXc

[0163] where where

[0164] is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine and Lis preferably located in the para position relative to Ya.

[0165] A further particularly preferred embodiment of the presentinvention, provides a novel compound of the formula VIII or the morespecific formula IX in which a1 is 3, a2 is zero, Ya is2,4-dimethyl-3-pentyloxy, a3 is 4, a4 is zero, a5 is 1, Ma is—CH₂—OCO—FeCp₂, a6 is 2 and L is —CH₂—O—CH₂— and which has the specificformula IXd

[0166] where

[0167] is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine, L ispreferably located in the para position relative to Ya, and

[0168] is FeCp₂.

[0169] A further particularly preferred embodiment provides mixturescomprising a metallocenyl phthalocyanine IV and at least onemetallocenyl phthalocyanine IX in which M₁ is Pd and X and Xa are eachBr, -L- is —CH₂— or —CH₂OCH₂—, x and a2 are each from 2 to 3, preferablyfrom 2.5 to 3, y and a3 are each 4 and z and a6 are each less than orequal to 2, where the content of metallocenyl phthalocyanine ormetallocenyl phthalocyanines IX is preferably from 10 to 30% by weight,based on the total mixture.

[0170] A further particularly preferred embodiment provides mixturescomprising a metallocenyl phthalocyanine IV and at least onemetallocenyl phthalocyanine IX in which M₁ is Cu, -L- is —CH₂— or—CH₂OCH₂—, x and a2 are each from 0 to 0.3, particularly preferably 0, Xand Xa are each Br, y and a3 are each 4 and z and a6 are less than orequal to 3, where the content of metallocenyl phthalocyanine ormetallocenyl phthalocyanines IX is preferably from 20 to 50% by weight,particularly preferably from 30 to 50% by weight, based on the totalmixture.

[0171] Furthermore, the present invention provides a process forpreparing the mixture of the invention by reacting a mixture Acomprising

[0172] (a) from 99 to 1% by weight of a phthalocyanine of the formula Iand

[0173] (b) from 1 to 99% by weight of a phthalocyanine of the formula IIwith a metallocene derivative in the presence of a catalyst.

[0174] In addition, the present invention provides a preferred processfor preparing the novel metallocenyl phthalocyanine compound IV orcompounds V to VIII by separating them from the reaction productobtained by the above process in a manner known per se and isolatingthem.

[0175] A further embodiment provides for the use of the compounds ormixtures of the invention or compounds or mixtures prepared by theprocesses of the invention for producing an optical recording medium.

[0176] A further embodiment provides an optical recording mediumcomprising a transparent substrate, a recording layer on this substrate,a reflection layer on the recording layer and, if desired, a protectivelayer on the reflection layer, where the recording layer comprises amixture according to the invention or a compound according to theinvention or a compound or mixture prepared by a process according tothe invention.

[0177] A further embodiment provides for the use of an optical recordingmedium according to the invention for optical recording, storage andreproduction of information, for producing diffraction-optical elementsor for the storage of holograms.

[0178] If desired, the optical recording medium of the invention maycomprise more than one recording layer and/or more than one reflectiveor partially reflective (semitransparent) layer.

[0179] The substrate which serves as support for the layers appliedthereto is generally semitransparent (i.e. has a transparency T of atleast 10%) or, preferably, transparent (T≧90%). The support can have athickness of from 0.01 to 10 mm, preferably from 0.1 to 5 mm.

[0180] The recording layer is preferably located between the transparentsubstrate and the reflective layer. The thickness of the recording layeris generally from 10 to 1000 nm, preferably from 50 to 500 nm,particularly preferably in the region of 100 nm, for example from 80 to150 nm. The absorption of the recording layer at the absorption maximumis usually in the range from 0.1 to 2.0, preferably from 0.5 to 2.0. Thethickness of the layer is very particularly preferably chosen in a knownmanner as a function of the respective index of refraction in theunwritten and written states at the reading wavelength so thatconstructive interference results in the unwritten state and, incontrast, destructive interference results in the written state, or viceversa.

[0181] The reflective layer, whose thickness is generally from 10 to 150nm, preferably has a high reflectivity (R≧70%) and a low transparency(T≦10%).

[0182] The uppermost layer, for example the reflection layer or therecording layer depending on the layer structure, is preferablyadditionally provided with a protective layer which generally has athickness in the range from 0.1 to 1000 μm, preferably from 0.1 to 50 μmand particularly preferably from 0.5 to 15 μm. This protective layer mayalso serve as bonding layer for a second substrate layer which isapplied thereto and preferably has a thickness of from 0.1 to 5 mm andconsists of the same material as the support substrate.

[0183] The reflectivity of the overall recording medium is preferably atleast 60%, particularly preferably at least 65%, at the writingwavelength of the laser used.

[0184] Suitable substrates are, for example, glasses, minerals, ceramicsand thermoset or thermoplastic polymers. Preferred supports are glassesand homopolymers and copolymers.

[0185] Suitable polymers are, for example, thermoplastic polycarbonates,polyamides, polyesters, polyacrylates and polymethacrylates,polyurethanes, polyolefins, polyvinyl chloride, polyvinylidene fluoride,polyimides, thermoset polyesters and epoxy resins. The substrate can bein pure form or further comprise customary additives, for example UVabsorbers or dyes as are proposed in JP 04/167 239 as light protectionfor the recording layer. In the latter case, it may be advantageous forthe dye added to the support substrate to have an absorption maximumwhich is shifted hypsochromically by at least 10 nm, preferably at least20 nm, relative to the dye of the recording layer.

[0186] The substrate is preferably transparent in at least part of therange from 600 to 830 nm, so that it transmits at least 90% of theincident light at the writing or reading wavelength. The substratepreferably has a spiral guide groove having a groove depth of generallyfrom 50 to 500 nm, a groove width of usually from 0.2 to 0.8 μm and aradial distance between adjacent grooves of generally from 0.4 to 1.6μm, particularly preferably a groove depth of from 100 to 300 nm and agroove width of from 0.3 to 0.6 μm, on the coated side.

[0187] Instead of the substrate, it is also possible, as described inEP-A 392 531, for the recording layer itself to have a groove.

[0188] The recording layer consists exclusively or essentially of one ormore phthalocyanines according to the invention. However, to increasethe stability further, it is possible for known stabilizers to be addedin customary amounts, e.g. a nickel dithiolate described in IP 04/025493 as light stabilizer. If desired, additional dyes can also be added,but advantageously in amounts of not more than 50% by weight, preferablynot more than 10% by weight, based on the recording layer. As theadvantages of the recording media of the invention depend on thephthalocyanines of the invention, it is advantageous for any added dyeto have an absorption maximum shifted hypsochromically relative to thephthalocyanine of the invention and for the amount of the added dye tobe kept so small that its contribution to the total absorption of therecording layer in the range from 600 to 830 nm is not more than 20%,preferably not more than 10%. However, particular preference is given toadding no additional dye.

[0189] Reflective materials suitable for the reflection layer are, inparticular, metals which readily reflect the laser radiation used forwriting and reproduction, for example the metals of the third, fourthand fifth main groups and the transition groups of the Periodic Table ofthe Elements. Particularly useful metals are Al, In, Sn, Pb, Sb, Bi, Cu,Ag, Au, Zn, Cd, Hg, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co,Ni, Ru, Rh, Pd, Os, Ir, Pt and the lanthanide metals Ce, Pr, Nd, Pm, Sm,Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and also their mixtures andalloys. For reasons of high reflectivity and ease of manufacture,particular preference is given to a reflection layer of aluminium,silver, copper, gold or alloys thereof.

[0190] Suitable materials for the protective layer are mainly syntheticpolymers which can be applied in a thin layer either directly of withthe aid of bonding layers to the support or the uppermost layer. It isadvantageous to choose mechanically and thermally stable polymers whichhave good surface properties and can be modified further, for exampleprinted on. Both thermoset polymers and thermoplastic polymers arepossible. Preference is given to radiation-cured (for example by meansof UV radiation) protective layers which are particularly simple andeconomical to produce. A large number of radiation-curing materials areknown. Examples of radiation-curing monomers and oligomers are acrylatesand methacrylates of diols, triols and tetrols, polyimides of aromatictetracarboxylic acids and aromatic diamines having C₁-C₄alkyl groups inat least two ortho positions relative to the amino groups, and oligomerscontaining dialkyl maleimidyl groups, for example dimethylmaleimidylgroups.

[0191] The recording media of the invention can also have additionallayers such as interference layers. If is also possible to constructrecording media having a plurality of recording layers (for example tworecording layers). The structure and use of such materials are known tothose skilled in the art. If interference layers are employed,preference is given to interference layers which are located between therecording layer and the reflective layer and/or between the recordinglayer and the substrate and consist of a dielectric material, forexample, TiO₂, Si₃N₄, ZnS or silicone resins as described in EP-A 353393.

[0192] The recording media of the invention can be produced by methodsknown per se using, as a function of the materials employed and the wayin which they function, various coating techniques.

[0193] Suitable coating methods are, for example, dipping, casting,painting, doctor blade coating and spin coating and also vapourdeposition processes carried out in a high vacuum. When using, forexample, casting methods, solutions in organic solvents are generallyemployed. When using solvents, it is preferably ensured that thesupports employed are not sensitive to the solvents. A particularlyadvantage of the dyes of the invention is that they are readily solubleeither as pure compounds or as mixtures of only a few components in lesspolar solvents, so that aggressive solvents such as acetone andcomplicated isomer mixtures can be dispensed with. Suitable coatingmethods and solvents are described, for example, in EP-A 401 791.

[0194] The recording layer is preferably applied by spin coating with adye solution. Solvents which have been found to be useful for thispurpose are, in particular, alcohols such as 2-methoxyethanol,cyclopentanol, isopropanol, isobutanol, diacetone alcohol, n-butanol oramyl alcohol, preferably cyclopentanol, diacetone alcohol or amylalcohol, or preferably fluorinated alcohols such as2,2,2-trifluoroethanol or 2,2,3,3-tetrafluoro-1-propanol and alsocyclohexane, methylcyclohexane, 2,6-dimethyl-4-heptanone and diisobutylketone or mixtures thereof, preferably amyl alcohol and2,6-dimethyl4-heptanone. Preference is also given to mixtures of dibutylether and 2,6-dimethyl4-heptanone or -heptanol.

[0195] Particular preference is also given to the incorporation ofadditives such as surfactants or quenchers, in particular peroxidequenchers, particularly preferably hydroquinone monomethyl ether, whichare usually used in amounts in the ppm range, e.g. in the range from 1to 10 ppm.

[0196] The metallic reflection layer is preferably applied by sputteringor vapour deposition under reduced pressure. Owing to the good adhesionto the support, the sputtering technique is particularly preferred forapplication of the metallic reflection layer. This technique iscomprehensively described both in textbooks (e.g. J. L. Vossen and W.Kern, “Thin Film Processes”, Academic Press, 1978) and in the prior art(e.g. EP-A 712 904), so that further details are unnecessary here.

[0197] The structure of the recording medium of the invention generallydepends mainly on the reading method; known functional principles aremeasurement of the change in the transmission or, preferably thereflection.

[0198] If the recording material is constructed for measurement of achange in the reflection, it is possible to employ, for example, thefollowing structures: transparent support/recording layer (one or morelayers)/reflection layer and, if appropriate, protective layer (notnecessarily transparent), or support (not necessarilytransparent)/reflection layer/recording layer and, if appropriate,transparent protective layers. In the first case, the light comes infrom the support side, while in the second case, the radiation comes infrom the side of the recording layer or, if present, the protectivelayer. In both cases, the light detector is on the same side as thelight source. The first structure of the recording material to be usedaccording to the invention is generally preferred.

[0199] If the recording material is constructed for measurement of achange in the light transmission, the following alternative structure,for example, is possible: transparent support/recording layers (one ormore layers) and, if appropriate, transparent protective layer. Thelight for writing or for reading can come in either from the supportside or the side of the recording layer or, if present, the protectivelayer, with the light detector in this case always being present on theopposite side.

[0200] A further embodiment of the present invention therefore providesan optical recording medium comprising a metallocenyl phthalocyanine ofthe invention or a mixture thereof or a metallocenyl phthalocyanineprepared according to the invention.

[0201] A preferred embodiment provides an optical recording mediumcomprising a transparent substrate, a recording layer on this substrate,a reflection layer on the recording layer and, if desired, a finalprotective layer, where the recording layer comprises a metallocenylphthalocyanine according to the invention or prepared according to theinvention or a mixture thereof.

[0202] Recording (inscription, writing) and reading of the informationis preferably carried out by means of laser radiation. Suitable lasersare, for example, commercial semiconductor diode lasers, for exampleGaAsAl, InGaAlP, GaAs or GaN laser diodes having a wavelength of 635,650, 670, 680, 780 or 830 nm or 390-430 nm, or gas/ion lasers, forexample He/Ne, Kr, HeCd or Ar lasers having a wavelength of 602, 612,633, 647, or 442 and 457 nm.

[0203] Recording is preferably carried out by inscribing pits ofvariable length by means of pulse-length-modulated laser radiationfocused on the recording layer. The recording speed chosen depends onthe focusing geometry and laser power and can be, for example, in therange from 0.01 to 100 m/s, preferably 1-50 m/s (corresponding 1× to40×) or even above, e.g.1× to 48×.

[0204] Reading of the information is preferably carried out by localizedmeasurement of reflection or transmission using laser radiation of lowpower and a photodetector. It is particularly advantageous to be able toemploy laser radiation of the wavelength used for recording, so that nosecond laser instrument has to be used. In a preferred embodiment,recording and reading of information are therefore carried out at thesame wavelength. During reading, the power of the laser used isgenerally reduced compared with the laser radiation used for recording,for example to from one tenth to one fiftieth. In the case of therecording materials used according to the invention, the information canbe read one or more times. Suitable photodetectors include, preferably,PIN and AV photodiodes and also CCDs (charge-coupled devices).

[0205] A further embodiment provides recording layers comprising thecompounds of the invention or mixtures thereof and also provides opticalrecording media which are produced therefrom and further compriseadditives such as stabilizers or dyes to modify the spectral propertiesor colour, with the additive content preferably being in the range from0.001 to 20% by weight, based on the recording layer.

[0206] Such dyes are known to those skilled in the art, for example fromEP-A 376 327, and include, for example, cyanines, coumarins, alantoindyes, azo dyes such as

[0207] thiazine dyes, triphenylmethane dyes, acridines, oxazines, bisazodyes such as

[0208] xanthenes or dipyromethenes as are known from EP-A 822 544.

[0209] The phthalocyanines of the invention make it possible forinformation to be stored with high reliability and stability and have avery good mechanical and thermal stability and also display a high lightstability and sharp edges of the pits. Particularly advantageousproperties are the high signal/noise ratio and the high opticalresolution which makes it possible to achieve defect-free recording andreading of the signals even at high speed (≧4×) and at the same time lowjitter.

[0210] The medium of the invention represents, in particular, an opticalinformation storage medium of the WORM type. It can be used, forexample, as playable CD (compact disc), as storage materials forcomputers and video recorders/players, as identity and security card orfor the production of diffraction-optical elements, for exampleholograms.

[0211] The invention therefore further provides for the use of therecording medium of the invention for optical recording, storage andreproduction of information, for producing diffraction-optical elementsor for the storage of holograms. Recording and reproduction arepreferably carried out in a wavelength range from 400 to 500 nm or,particularly preferably, from 600 to 830 nm.

[0212] A further embodiment of the present invention provides for theuse of the mixtures of the invention and the novel compounds of theformulae IXa to IXd for producing writable optical recording media, withthe writing speed being greater than or equal to 8×, preferably greaterthan or equal to 16×, particularly preferably greater or equal to 32×,and very particularly preferably greater than or equal to 48×.

[0213] As a result of the use of the dyes of the invention, therecording media of the invention advantageously have homogeneous,amorphous and low-scattering recording layers whose absorption edge inthe solid phase is steep. Further advantages are the high lightstability in daylight and under laser radiation of low power densitycombined with high sensitivity under laser radiation of high powerdensity, the uniform writing width, the good thermal and storagestability and also, in particular, the high optical resolution and thevery low jitter.

EXAMPLES Example 1

[0214] 97 g of copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine(“substance 1”, prepared as described in EP 712 904) together with 95 gof N-methylformanilide are introduced into 170 g of chlorobenzene. Afterheating the mixture to 50° C., 107 g of phosphorus oxychloride aremetered in at 48-52° C. over a period of 4 hours. The reaction mixtureis then stirred at this temperature for 18 hours. After the reaction hasended, the mixture is poured into a prepared solution of 550 g of sodiumacetate in 450 ml of deionized water. The reaction vessel is rinsed withabout 100 ml of chlorobenzene. The mixture (emulsion) obtained isstirred vigorously for 30 minutes and then allowed to stand for 1 hourwith the stirrer switched off so that the phases separate. Afterseparating off the aqueous phase, the chlorobenzene phase is washedtwice with 200 ml each time with water and is dewatered under reducedpressure. The volume of the solution is adjusted to 600 ml withchlorobenzene, and 100 g of silica gel 60 are then added. The resultingsuspension is stirred at 25° C. for one hour and subsequently filtered.The residue is washed 4 times with 200 ml each time of chlorobenzene.

[0215] The combined chlorobenzene filtrates are distilled under reducedpressure until 300 ml remain and this is then poured into 3.5 l ofmethanol at 25° C. The suspension obtained is cooled to 10° C. andfiltered. The filtercake obtained is washed 3 times with 250 ml eachtime of methanol and subsequently 4 times with 500 ml each time ofdeionized water. Drying in a drying oven gives 88 g of a mixture ofcopper monoformyl-, diformyl- andtriformyl-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine (“substance2”) having the following properties:

UV/VIS: ε=160 000 l·mol⁻¹·cm⁻¹;λmax=712 nm (in NMP)

HPLC(area): Starting material<0.2%; monoaldehyde: 68%; di-+trialdehyde:32%

Example 2

[0216] 88 g of “substance 2” obtained in Example 1 are dissolved in 300g of tetrahydrofuran (THF). After addition of 18 g of methanol, asuspension of 2.5 g of sodium borohydride in 30 g of THF is metered inat 20° C. at a uniform rate over a period of 30 minutes.

[0217] The mixture is then stirred for another three hours at 20-25° C.After the reaction is complete, excess NaBH₄ is removed by addition of2.5 g of anhydrous acetic acid.

[0218] The reaction mixture is then clarified by filtration through alayer of 90 g of silica gel (Becosorb 1000)/THF. The silica gel layer iswashed twice with 90 g each time of THF and the combined filtrates aredistilled until a volume of 300 ml remains.

[0219] The concentrated solution is poured at a uniform rate into 3.5 lof water at 25° C. over a period of 3 hours while stirring vigorously,the resulting product suspension is filtered and the filtercake iswashed with deionized water.

[0220] Drying in a drying oven at 70° C. and a pressure of 100 mbargives 86 g of a mixture of copper mono(hydroxymethyl)-,di(hydroxymethyl)- andtri(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine(substance 3) having the following property:

UV/VIS: λmax=719 nm (in NMP)

[0221] Using a similar method, a mixture of palladiummono(hydroxymethyl)-, di(hydroxymethyl)- andtri(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine canbe obtained when palladiumtetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine (prepared as describedin EP-A 712 904) is used as starting material in Example 1.

Example 3

[0222] 50 g of substance 3 from Example 2 are introduced into 310 g oftoluene and stirred at 25° C. until all the solid has gone intosolution. A suspension of 31 g of ferrocenecarboxylic acid in 650 g ofanhydrous THF is then added. 0.2 g of 98% sulphuric acid as catalyst isthen introduced into the stirred reaction mixture. The reaction mixtureis heated to boiling (about 74° C.) and the THF is distilled off fromthe reaction mixture via a Vigreux column at a uniform rate over aperiod of three hours. The water formed during the reaction is removedat the same time. The internal temperature is allowed to rise from aninitial 74° C. to 100° C. At this temperature, the distillation isinterrupted and the mixture is refluxed for another three hours.Distillation is then recommenced and the internal temperature isincreased to 107° C. over a period of one hour by distilling off THF.The reaction mixture is then cooled to 25° C. and filtered through asuction filter to remove excess ferrocenecarboxylic acid. The residue onthe filter is washed twice with 25 g each time of toluene. 50 g ofsilica gel (Becosorb 1000) and 5 g of activated carbon are introducedinto the combined toluene filtrates, the mixture is stirred at 25° C.for one hour, filtered through a suction filter and the residue iswashed 4 times with 100 ml each time of toluene. The combined filtratesare distilled at 250 mbar until 175 g remain, cooled to room temperatureand introduced into 1600 ml of a mixture of methanol with 5% by volumeof water at 0-5° C. to precipitate the end product. After stirring forone hour, the mixture is filtered and the filtercake is washed threetimes with 140 ml of cold methanol (containing 5% by volume of water)and then three times with 140 ml of water. Drying in a vacuum dryingoven at 80° C. and 130 mbar gives a product having the followingproperties:

[0223] λ_(max)=713.5 nm (in dibutyl ether);

[0224] HPLC: Column: C18 reversed phase column

[0225] Mobile phase: Gradient of methanol and tetrahydrofuran

[0226] Detector: 319 nm

[0227] (a) Main components: Ferrocenoyl-substituted coppermono(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine fromExample 2

[0228] (b) Dimers+trimers appear as unresolved peak group after thecomponents of the monomers.

[0229] Total content of dimeric and trimeric phthalocyanine derivatives(LC area): 36%

[0230] Using a similar method, a mixture of ferrocenoyl-substitutedand/or etherified palladium mono(hydroxymethyl)-, di(hydroxymethyl)- andtri(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanines andtheir dimers and trimers can be obtained when the mixture of palladiummono(hydroxymethyl)-, di(hydroxymethyl)- andtri(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanineswhich can be obtained as described in Example 2 is used as startingmaterial.

[0231] Using a similar method, a mixture of ferrocenoyl-substitutedand/or etherified palladium and copper mono(hydroxymethyl)-,di(hydroxymethyl)- andtri(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanines andtheir dimers and trimers can be obtained when the mixture of palladiummono(hydroxymethyl)-, di(hydroxymethyl)- andtri(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanineswhich can be obtained as described in Example 2 and substance 2 fromExample 2 are used as starting materials in a ratio of, for example,1:1.

Example 3a

[0232] 50 g of brominated palladiummono(hydroxymethyl)tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine(prepared as described in Example 2, from WO 00/09522) are introducedinto 310 g of toluene and stirred at 25° C. until all the solid has goneinto solution. A suspension of 17.2 g of ferrocenecarboxylic acid in 650g of anhydrous THF is then added. 0.3 g of 98% sulphuric acid ascatalyst is then introduced into the stirred reaction mixture. Thereaction mixture is heated to boiling (about 74° C.) and the THF isdistilled off from the reaction mixture at a uniform rate over a periodof three hours. The water formed during the reaction is removed at thesame time. The internal temperature is allowed to rise from an initial74° C. to 113° C. The reaction mixture is then cooled to 25° C. andfiltered through a suction filter to remove excess ferrocenecarboxylicacid. The residue on the filter is washed twice with 25 g each time oftoluene. 50 g of silica gel (Becosorb 1000) and 5 g of activated carbonare introduced into the combined toluene filtrates, the mixture isstirred at 25° C. for one hour, filtered through a suction filter andthe residue is washed 4 times with 100 ml each time of toluene. Thecombined filtrates are distilled at 250 mbar until 180 g remain, cooledto room temperature and introduced into 1800 ml of acetonitrile at 0-5°C. to precipitate the end product. After stirring for one hour, themixture is filtered and the filtercake is washed three times with 140 mlof cold acetonitrile and then three times with 140 ml of water. Dryingin a vacuum drying oven at 80° C. and 130 mbar gives a product havingthe following properties:

[0233] λ_(max)=712.5 nm (in dibutyl ether);

[0234] HPLC: Column: C18 reversed phase column

[0235] Mobile phase: Gradient of methanol/tetrahydrofuran

[0236] Detector: 319 nm

[0237] Dimers+trimers appear as unresolved peak group after thecomponents of the monomeric compound (monomers are identical to thesample prepared in Example 8 of WO 00/09522) Total content of dimericand trimeric phthalocyanine derivatives (LC area): 17%

[0238] Using a similar method, a mixture of ferrocenoyl-substitutedand/or etherified palladiummono(hydroxymethyl)tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanines andtheir dimers and trimers when unbrominated palladiummono(hydroxymethyl)tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine(prepared as described in EP-A 712 904) is used as starting materials.

Example 3b

[0239] Example 3 is repeated using 1.2 g of p-toluenesulphonic acidinstead of 0.2 g of sulphuric acid.

[0240] This gives a product having the following properties:

[0241] λ_(max)=713 nm (in DBE);

[0242] Dimers and trimers: 32% LC area

Example 4

[0243] 0.5 g(3.5 mmol) of calcium hypochlorite and 15 ml of water areplaced in a 25 ml round-bottom flask and, while cooling (0-5° C.) andunder an inert gas atmosphere (nitrogen), 1.5 ml of acetic acid areadded. After stirring for 2 to 3 minutes, a light-yellow solution isobtained. 3.0 g (2.4 mmol) of the product as described in Example 3 in60 ml of dichloromethane are added to this solution at 0-5° C. Themixture is then stirred at room temperature for another 3 hours. Thereaction mixture is washed in succession with 10% of NaHCO₃ solution andtwice with water, then dried over MgSO₄, filtered and purified by meansof flash chromatography. The purified product is dissolved in 20 ml ofTHF and precipitated by addition of water (300 ml). The greenprecipitate obtained in this way is filtered off, then washed twice withwater and dried overnight at 60° C./160 mbar. This gives 2.01 g (65% oftheory) of a chlorinated mixture of ferrocenyl-substituted coppermono(hydroxymethyl)-, di(hydroxymethyl)- andtri(hydroxymethyl)tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanineshaving the following properties: UV/VIS: λ_(max)=716.5 nm (EtOH),chlorine content=1.97%, iron content=5.1%.

[0244] TGA: Point of inflection of the decomposition curve=257° C.

Example 5

[0245] In a 250 ml round-bottom flask provided with magnetic stirrer andnitrogen blanketing, 10 g (9.4 mmol) of the product as described inExample 1 in 135 ml of chlorobenzene are added at 0-5° C. to a mixtureof 0.6 g (4.2 mmol) of calcium hypochlorite, 15 ml of water and 1.5 mlof acetic acid. The green solution is stirred at room temperature for 3hours.

[0246] The mixture is then worked up as described in Example 4. Thisgives 8.17 g (79% of theory) of a chlorinated mixture of coppermonoformyl-, diformyl- andtriformyl-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanines having thefollowing properties: λ_(max)=714 nm (EtOH), chlorine content=2.1%, IR:C=0 band at 1636 cm⁻¹.

Example 6

[0247] A 2.5% strength by weight solution of a “substance 6a” (preparedas described in Examples 1 to 3 but using amounts of N-methylformanilideand POCl₃ reduced by 15% in comparison with Example 1 and an amount ofNaBH₄ reduced by 15% in comparison with Example 2) (oligomer content 32%by weight) in a mixture of tert-amyl alcohol and2,6-dimethyl-4-heptanone (90:10) is filtered through a Teflon filterhaving a pore opening of 0.2 μm and applied to the surface of a 1.2 mmthick, grooved (groove depth: 225 nm, groove width: 575 nm, groovespacing: 1.6 μm) disc by spin coating at a speed of rotation of 500 rpm.The excess of solution is spun off by increasing the speed of rotation.The uniformly applied layer is then dried at 70° C. in a convection ovenfor 20 minutes. The absorption spectrum is measured over the visiblespectrum by means of a spectrophotometer, and the wavelength of theabsorption maximum (λ_(max)) is determined as 732 nm. A 60 nm thicksilver layer is subsequently deposited on the resulting recording layerin a vacuum coating apparatus (Swivel, Balzers). An 8 μm thickprotective layer of a UV-curing photopolymer (650-020 from DSM) is thenapplied thereto by spin coating. The disc produced in this way is testedby means of a commercial tester (Pulstec OMT 2000) at a writing speed of4×(4.8 m/s) and the optimum writing power according to the “Orange Book”(Optimum Power Control and Recording Conditions) is determined as 13.8mW. The measured results are shown in Table A below.

Example 7

[0248] Example 6 is repeated using a “substance 6b” prepared asdescribed in Examples 1 to 3, but, unlike Example 3, the reaction isstopped after a hold time of 3 hours at 100° C. and the internaltemperature is not allowed to rise beyond 100° C. (oligomer content: 41%by weight). The absorption maximum (λ_(max)) is in this case determinedas 733.3 nm and the optimum writing power is found to be 13.1 mW. Themeasured results of Examples 6 and 7 are summarized in Table A. TABLE AOligomer content λ_(max) [nm] Optimum laser power [mW] Example 6 32% 73213.8 Example 7 41% 733.3 13.1

Example 8

[0249] A 2.5% strength by weight solution of a compound analogous to“compound 6a” as described in Example 6 but having an oligomer contentof 30% in a mixture of tert-amyl alcohol and 2,6-dimethyl-4-heptanone(90:10) is filtered through a Teflon filter having a pore opening of 0.2μm and applied to the surface of a 1.2 mm thick, grooved (groove depth:225 nm, groove width: 575 nm, groove spacing: 1.6 μm) disc by spincoating at a speed of rotation of 500 rpm. The excess of solution isspun off by increasing the speed of rotation. The uniformly appliedlayer is then dried at 70° C. in a convection oven for 20 minutes. Theoptical density of the dye layer is measured at a wavelength of 680 nmby means of a photometer (Dr. Schenk). A 60 nm thick silver layer issubsequently deposited on the resulting recording layer in a vacuumcoating apparatus (Swivel, Balzers). An 8 μm thick protective layer of aUV-curing photopolymer (650-020 from DSM) is then applied thereto byspin coating.

[0250] This production procedure is repeated at different speeds ofrotation in the spin coating step to produce discs having variousoptical densities. Data are written onto the discs produced in this wayby means of commercial CD burners at various writing speeds (1× to 12×).For each writing speed and each optical density, the dynamic signalparameters are subsequently determined by means of a fully automatic CDtest system (CD-Cats SA3, Audio Development) and compared with the“Orange Book” specifications. All discs which fully meet thespecifications for all writing speeds are within the “processingwindow”. Conversely, discs for which at least one parameter does notmeet the specifications lie outside the window. The width of the“processing window” is defined by the difference between the highest andlowest optical densities of the discs within the “processing window”. Inthis context, the optical density (OPD) is defined as 1000 times theabsorption at 680 nm (Dr. Schenk photometer). For example, theprocessing window can be from OPD=295 to OPD=310 and thus have a widthof 15. The wider the “processing window”, the more tolerant is theproduction process for high-quality discs.

[0251] For speeds from 1× (Philips) to 8× (Teac) a width of the“processing window” of 9 is determined, while for 1× (Philips) to 12×(Plextor), a window of 2 is determined.

Example 9

[0252] Example 8 is repeated using a compound analogous to “compound 6a”as described in Example 6 but with an oligomer content of 37%. The widthof the “processing window” is 16 for from 1× to 8×, and 13 for from 1×to 12×, cf. Table B. TABLE B Width of processing window [optical densityOligomer points] content Philips1x - Teac8x Philips1x - Plextor12xExample 8 30% 9 2 Example 9 37% 16 13

Example 10

[0253] 25 g of the substance as described in Example 3 are applied to apreparative column (length of separation section: 1.2 m, diameter: 5 cm,silica gel 60 (Merck), eluant: toluene) and eluted by means of a toluenesolution. The fractions comprising the monomers, dimers and the higheroligomers are collected individually and the eluates are subsequentlyevaporated. The precipitate is dried for 12 hours at 60° C./165 mbar.The wavelengths of the absorption maximum (20 mg/l in t-amyl alcohol,d=0.5 cm) and the content (% by weight) of bound iron of the fractionsare shown in Table C. TABLE C Fraction λ Fe Monomers 712.5 nm 4.9%Dimers 3.1% Higher 1.6% oligomers

[0254] The dimers consist mainly of phthalocyanines having thecomposition

[0255] where

[0256] is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine

[0257] is FeCp₂.

[0258] The “higher oligomers” are essentially trimeric compounds plussmaller amounts of tetramers and higher oligomers. The main part of thisfraction is composed essentially of the following components:

Example 11

[0259] A 2% strength by weight solution (tert-amyl alcohol) of thesubstance as described in Example 3 is applied to a glass support byspin coating and dried at 70° C. in an oven for 20 minutes. Thethickness of the dry dye layer is 50 nm. This results in a transparenthomogeneous layer having a green colour and a maximum absorption of0.545A at λ_(max)=734 nm and an absorption of 0.137A at 780 nm.

[0260] A layer of the substance as described in Example 3a produced in asimilar manner has a maximum absorption of 0.58A at λ=730 nm and anabsorption of 0.131A at 780 nm.

Example 12

[0261] 25 g of the substance as described in Example 3a are fractionatedby a method similar to Example 10. The fraction comprising the monomersis discarded and the fraction comprising the dimers and oligomers iscollected and dried. A 2% strength by weight solution (tert-amylalcohol) of this substance is applied to a glass support using a methodsimilar to Example 11 and the absorption spectrum of the solid ismeasured over the visible wavelength range of 400-800 nm. The absorptionmaximum of the substance comprising dimers and higher polymers isdetermined as λ=737 nm, compared with a mixture as described in Example6 for which 732 nm is determined.

Example 13

[0262] The components of a mixture of ferrocenoyl-substituted and/oretherified copper mono(hydroxymethyl)-, di(hydroxymethyl)- andtri(hydroxymethyl)-tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyaninemonomers and oligomers as described in Example 3 are separated on apreparative column as described in Example 10. The thermodynamicproperties of the dried fractions are subsequently determined by meansof DSC (Mettler-Toledo Star-System, 35° C. 45 min, 35-450° C. 4° C./min,Tiegel HP gold-plated 50 l) and TGA (Mettler-Toledo Star System, 35-420°C. 10° C./min, N2 200 ml/min, Tiegel alumina 50 l). The DSC curve isflat up to about 200° C. No melting point (endothermic) is observed. Afraction-specific, exothermic decomposition peak appears in the range180-320° C., with the onset temperature of the monomers being higher andthe endset temperature being lower than those of the dimers, the higheroligomers and the mixture (cf. Table D).

[0263] The corresponding TGA data for the fractions, including 1:1monomer/dimer mixtures (mixture A) and monomer/higher oligomer mixtures(mixture B) are shown in Table E. TABLE D Integral Fraction Onset Peakexoth. Endset exoth. Monomers 220° C. 255° C. 270° C.  45 J/g Dimers190° C. 230/270° C. 310° C. 105 J/g Higher oligomers 185° C. 270° C.320° C. 170 J/g Mixture 185° C. 255° C. 320° C.  60 J/g

[0264] TABLE E Point of Fraction Step Onset inflection Midpoint Monomers−34% 282° C. 308° C. 317° C. Dimers −34% 292° C. 335° C. 329° C. Higheroligomers −34% 295° C. 312° C. 326° C. Mixture A −37% 290° C. 337° C.324° C. Mixture B −35% 294° C. 333° C. 326° C.

Example 14

[0265] A 2% strength by weight solution (tert-amyl alcohol) of thesubstance as described in Example 3 is applied to a glass support bymeans of spin coating and dried at 70° C. in an oven for 20 minutes. Thedye layer (green) is covered with a second glass support. The two glasssupports are subsequently fixed together by means of a metal clamp. Fivesuch specimens are heated to 240° C. in an oven. A specimen is thentaken out and the temperature is increased to 245° C., another specimenis taken out and the temperature is increased to 250° C., and so forth.Visual inspection of the cool specimens shows that the dye layer fadesin the range from 250° C. to 255° C. (colour change from green toyellow). Photometric measurement of the absorption spectra confirms thatthe long-wavelength absorption band gradually disappears in the rangefrom 245° C. to 260° C., with the greatest decrease occurring in therange 250-255° C.

[0266] The substance as described in Example 3a displays similar fadingbehaviour, but the absorption band has disappeared by 255° C.

Example 15

[0267] 2% strength by weight solutions (tert-amyl alcohol) of thesubstances as described in Example 3 and Example 3a are each applied byspin coating to a smooth (groove-free) polycarbonate disc substrate anddried at 70° C. in an oven for 20 minutes. The reflection spectra andthe transmission spectrum of the dye layer are subsequently measured bymeans of an array spectrometer (ETA Optik) in the range 390-1000 nm, andthe complex index of refraction (n-ik) over the spectrum and the layerthickness were determined therefrom. The values at the wavelengths 780nm, (n_(max)) and (k_(max)) are shown in Table F. TABLE F Substance 3Substance 3a 780 nm 758 nm 728 nm 780 nm 754 nm 723 nm n − ik 2.27 −i0.090 2.58 − i0.530 1.82 − i1.260 2.27 − i0.075 2.58 − i0.546 1.84 −i1.320 (n_(max)) (k_(max)) (n_(max)) (k_(max))

Example 16

[0268] 25 g of the substance as described in Example 3a are fractionatedby a method similar to Example 10. The fraction comprising the monomersis discarded and the fraction comprising the dimers and higher oligomersis collected and dried. This is subsequently used to produce a disc in amanner similar to Example 8. It is found that good-quality discs can beachieved at a layer thickness which is about 10% lower.

Example 17

[0269] Using a 2% strength by weight solution of a substance asdescribed in Example 3 in a mixture of tert-amyl alcohol and2,6-dimethyl-4-heptanone (90:10) which has been filtered through a 0.2μm Teflon filter, CD-R's (74 min.) are produced on a production line(Steag) by a method similar to that described in Example 6 (groovedepth: 212 nm, groove width (half height): 565 nm, wall inclination:63°, reflector: 70 nm Ag, protective layer: 8 μm). The spinning processis carried out in such a manner that the optical density of therecording layer is 360 units (ETA-Optik photometer).

[0270] The discs are written on at various writing speeds from 1× to 16×(Audio Tracks) on various commercial CD-R recorders (Philips CDD3600,Yahama 8424RW, Teac R558S Panasonic CW7503, Plextor 8220, Plextor 12432,Sanyo 12×, Yahama 2100 16×) and analysed by means of a CDA SL100 testsystem (CD Associates). Result: All the discs tested meet the “OrangeBook” specifications.

Example 18

[0271] Using a 3% strength by weight solution of a substance asdescribed in Example 3a in a mixture of dibutyl ether and2,6-dimethyl-4-heptanone (97:3) which has been filtered through a 0.2 μmTeflon filter, CD-R's (74 min.) are produced on a production line(Steag) by a method similar to that described in Example 17 and tested.Result: All discs tested meet the “Orange Book” specifications.

Example 19

[0272] To determine the properties at high recording speeds, the discsproduced as described in Example 17 are written on at various speeds(16×, 24×, 32×) using various layer powers and writing strategies(defined in the “Orange Book”, Part II, Vol. 2, Multi-Speed CD-R) on alaboratory system (noncommercial) and subsequently tested. The followingoptimum writing parameters or jitter values (mean of 3T to 11T jitter in% of 1T) are found (Table G): TABLE G Speed Θ ΔT/T ΔP/P_(op) PowerP_(opt) Land jitter Pit jitter 16× −0.5T 0.18 6% 21 mW 9%  9% 24× −0.5T0.23 7% 26 mW 10%  11% 32× −0.5T 0.25 7% 34 mW 9% 11%

Example 20

[0273] Using a 3% strength solution of a substance as described inExample 3 in a mixture of dibutyl ether and 2,6-dimethyl-4-heptanone(97:3) which has been filtered through a 0.2 μm Teflon filter, discs areproduced as described in Example 9b. A disc chosen at random is writtenon at a speed of 48 m/s (40×) (Θ=−0.5TΔP/P_(opt)=10%) on a commercialtest system (Pulstec DUU 1000) and subsequently tested. The results aresummarized in Table H (for the meanings of the parameters, see “OrangeBook”, Part II, Vol. 2, Multi-Speed CD-R). TABLE H Pwr Time BLER SymRefl I3 I11 I3R I11R 46 53.02′ 3182″ 3 −0.7 66.7% 0.304 0.629 0.3570.737 mW PP_(min) PP_(max) JL3T JL11T JP3T JP11T DL3T DL11T DP3T DP11T 00 38 ns 30 ns 42 ns 30 ns −56 ns 32 ns −50 ns 12 ns

Example 21

[0274] 2.75% by weight of a substance as described in Example 3 and0.25% by weight of a substance A are dissolved in a solvent mixture ofdibutyl ether and 2,6-dimethyl-4-heptanone (97:3). The solution isfiltered though a 0.2 μm Teflon filter and then used to produce discshaving a recording layer which has a colourless (metallic) appearance bya method similar to Example 17. A similar effect is achieved using 2.70%by weight of a substance as described in Example 3a and 0.3% by weightof a substance B.

Example 22

[0275] The solution spun off during the spinning process in theproduction of discs as described in Example 17 is collected in a closedcontainer. After a production time of 24 hours, the container is changedand the solution is analysed photometrically and by gas chromatography.After addition of the amounts of the two solvent components required toreestablish the desired concentrations, the solution is returned to theproduction circuit. The quality of the discs is checked periodically.After 10 cycles, no change in the quality is found.

[0276] The recycling process is likewise carried out for the productionprocesses of Examples 18 and 20 over 10 cycles without a deteriorationin quality.

What is claimed is:
 1. A mixture of metallocenyl phthalocyanines,obtainable by reacting a mixture A comprising (a) from 1 to 99% byweight, preferably from 50 to 95% by weight, of a phthalocyanine of theformula I

where M₁ is a divalent metal, an oxo-metal group, a halo-metal group ora hydroxy-metal group or two hydrogen atoms, where one or two ligandsmay be bound to the divalent metal atom, the oxo-metal group, thehalo-metal group or the hydroxy-metal group, X is halogen such aschlorine, bromine or iodine, preferably chlorine or bromine, Y₁ is —OR₁,—OOC—R₂, —NHR₁, —N(R₁)R₂, —SR₁, preferably —OR₁, Y₂ is —CHO,—CH(OR₃)OR₄, —CH═N—OH, —CH═N—OR₃, —CH═N—NHR₅, —CH═N—N(R₃)R₅, —CH₂OH,—(CH₂)₂₋₂₀OH, —CH₂OR₃, —CH₂OOC—R₃, —CO—R₃, —COOH or —COOR₃, R₁ to R₅ caneach be, independently of one another, unsubstituted or halogen-,hydroxy-, C₁-C₂₀alkoxy-, C₁-C₂₀alkylamino- orC₂-C₂₀dialkylamino-substituted C₁-C₂₀alkyl, which may be interrupted by—O—, —S— or —NR₁₁—, where R₁₁ can be C₁-C₆alkyl, and R₁ and R₂ may alsobe C₅-C₂₀cycloalkyl, C₂-C₂₀alkenyl, C₅-C₁₂cycloalkenyl, C₂-C₂₀alkynyl,C₆-C₁₈aryl or C₇-C₁₈aralkyl, x is a rational number from 0 to 8,preferably from 0 to 5, particularly preferably from 0 to 3, y₁ is arational number from 0 to 6, preferably an integer from 1 to 6,particularly preferably from 3 to 5, very particularly 4, y₂ is arational number from 0 to 4, preferably from 0 to 2, particularlypreferably from 0 to 1, where (x+y ₁ +y ₂)≦16, and R₁₅ can be ahydroxyl-containing radical, a carboxyl-containing radical or a radicalcontaining an acid chloride group, preferably —CH₂OH, —CH(Me)OH, —COOH,—COCl, and (b) from 99 to 1% by weight, preferably from 50 to 5% byweight, of a phthalocyanine of the formula II

with a metallocene derivative in the presence of a catalyst.
 2. Amixture according to claim 1 or 2 which comprises the following maincomponents: (a) from 1 to 99% by weight of a metallocenyl phthalocyanineor its metal complex with a divalent metal, oxo-metal, halo-metal orhydroxy-metal, in which at least one of the four phenyl rings of thephthalocyanine bears at least one metallocene radical as substituentbound via a bridging unit E, where E comprises a chain of at least twoatoms or atom groups selected from the group consisting of —CH₂—,—C(═O)—, —CH(C₁-C₄alkyl)-, —C(C₁-C₄alkyl)₂-, —NH—, —S— and —O—, and (b)from 99 to 1% by weight of a metallocenyl phthalocyanine compoundselected from the group consisting of phthalocyanine compoundscomprising two phthalocyanine units linked via a single bond or abridging atom or molecule, phthalocyanine compounds comprising threephthalocyanine units linked in each case via a single bond or a bridgingatom or molecule and phthalocyanine compounds comprising fourphthalocyanine units linked in each case via a single bond or a bridgingatom or molecule.
 3. A metallocenyl phthalocyanine compound selectedfrom the group consisting of phthalocyanine compounds V comprisingtwo-phthalocyanine units linked via a single bond or a bridging atom ormolecule, phthalocyanine compounds VI comprising three phthalocyanineunits linked in each case via a single bond and/or a bridging atom ormolecule and phthalocyanine compounds VII comprising four phthalocyanineunits linked in each case via a single bond and/or a bridging atom ormolecule.
 4. A metallocenyl phthalocyanine of the formula VIII(Pc)_(a1),(Xa)_(a2)(Ya)_(a3)(Za)_(a4)(Ma)_(a5)(-L-)_(a6)   VIII where Pcis phthalocyanine or its metal complex of a divalent metal, oxo-metal,halo-metal, hydroxy-metal or 2 hydrogen atoms, Xa, Ya, Za, Ma and -L-are substituents on the peripheral carbon skeleton, in particular Xa ishalogen, Ya is substituted or unsubstituted alkoxy, alkylamino oralkylthio, Za is a formyl, carbonyl, hydroxymethyl or carboxy group, Mais a substituent comprising at least one metallocene radical, -L- is asingle bond, —(CH₂)_(a7)—, where a7=1, 2, 3 or 4, an ether group such as—O— or —(CH₂)_(a7)—O—(CH₂)_(a8), where a8=1, 2, 3 or 4, an ester group,an amide group or a divalent metallocenyl group, and al is 1, 2, 3, 4,5, 6, 7, 8, 9 or 10, a2 is a rational number from 0 to 8, preferablyfrom O to 5, particularly preferably from 0 to 3, a3 is a rationalnumber from 0 to 6, preferably an integer from 1 to 6, particularlypreferably from 3 to 5, very particularly preferably 4, a4 is a rationalnumber from 0 to 4, preferably from 0 to 2, particularly preferably from0 to 1, a5 is a rational number from 0 to 4, preferably from 0 to 2, a6is a rational number from 1 to 4, preferably from 1 to 3,where(a2+a3+a4+a5+a6)<16and 1≦(a4+a5+a6)≦4.
 5. A compound according toclaim 4, in which a1 is 1, a2 is zero, Ya is 2,4-dimethyl-3-pentyloxy,a3 is 4, a4 is zero, a5 is zero, a6 is 1 and L is —CH₂—O—CH₂— and whichhas the formula IXa

where

is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine and L ispreferably located in the para position relative to Ya.
 6. A compoundaccording to claim 4 in which a1 is 2, a2 is zero, Ya is2,4-dimethyl-3-pentyloxy, a3 is 4, a4 is zero, a5 is 1, Ma is—CH₂—OCO—FeCp₂, a6 is 1 and L is —CH₂—O—CH₂— and which has the formulaIXb

where

is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine, L ispreferably located in the para position relative to Ya and

is FeCp₂.
 7. A compound according to claim 4 in which a1 is 3, a2 iszero, Ya is 2,4-dimethyl-3-pentyloxy, a3 is 4, a4 is zero, a5 is 0, a6is 2 and L is —CH₂—O—CH₂— and which has the formula IXc

where

is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine and L ispreferably located in the para position relative to Ya.
 8. A compoundaccording to claim 4 in which a1 is 3, a2 is zero, Ya is2,4-dimethyl-3-pentyloxy, a3 is 4, a4 is zero, a5 is 1, Ma is—CH₂—OCO—FeCp₂, a6 is 2 and L is —CH₂—O—CH₂— and which has the formulaIXd

where

is copper tetra(α-2,4-dimethyl-3-pentyloxy)phthalocyanine, L ispreferably located in the para position relative to Ya and

is FeCp₂.
 9. A process for preparing a mixture according to claim 1,which comprises reacting a mixture A comprising (a) from 1 to 99% byweight of a phthalocyanine of the formula I according to claim 1 and (b)from 99 to 1% by weight of a phthalocyanine of the formula II accordingto claim 2 with a metallocene derivative in the presence of a catalyst.10. A process for preparing the metallocenyl phthalocyanine compound orcompounds according to claim 4, which comprises separating it/them offfrom the reaction product obtained according to claim 9 and isolatingit/them.
 11. The use of compounds according to any of claims 1 to 4 orprepared according to claim 9 or 10 for producing an optical recordingmedium.
 12. An optical recording medium comprising a transparentsubstrate, a recording layer on this substrate, a reflection layer onthe recording layer and, if desired, a protective layer, wherein therecording layer comprises a mixture according to any of claims 1 to 4 orprepared according to claim 9 or
 10. 13. The use of an optical recordingmedium according to claim 12 for optical recording, storage andreproduction of information, for producing diffraction-optical elementsor for the storage of holograms.
 14. The use of mixtures according toany of claims 1 to 4 and of compounds according to any of claims 5 to 8for producing writable optical recording media, wherein the writingspeed is greater than or equal to 8×, preferably greater than or equalto 16×, particularly preferably greater than or equal to 32× and veryparticularly preferably greater than or equal to 48×.